ELASTIN PRODUCTION AND DEGRADATION IN CUTIS LAXA ACQUISITA

A case of cutis laxa acquisita was studied with the aim of defining th e molecular defects involved and comparing them with those of an inher ited form of cutis laxa. In the acquisita form of cutis laxa ultrastru ctural and biochemical observations confirmed a dramatic reduction of dermal elastin, whereas collagen content was normal. Elastin mRNA expr ession as well as tropoelastin production by dermal fibroblasts, in vi tro, were normal compared with control cells, as revealed by in situ h ybridization and enzyme-linked immunosorbent assay, respectively. Lysy l oxidase activity, measured on cultured fibroblasts, was reduced to 6 0% compared with age-matched control subjects. Unlike control skin fib roblasts or fibroblasts from inherited cutis laxa, the affected skin c ells from cutis laxa acquisita predominantly expressed an elastolytic activity identified as cathepsin G. Patient serum also has reduced ela stase inhibitory capacity and reduced levels of alpha 1-antiproteinase inhibitor (alpha 1-antitrypsin). Although cutis laxa acquisita is a h eterogeneous group of disorders, findings in this patient were consist ent with excessive loss of cutaneous elastin due to the combined effec ts of several factors, such as low lysyl oxidase activity together wit h high levels of cathepsin G and reduction of circulating proteinase i nhibitor(s).